1. Field of the Invention
The present invention relates to steering wheel assemblies with particular emphasis placed on use in motor vehicles. More particularly the invention relates to the hub or pad of a steering wheel assembly used in motor vehicles and apparatus for maintaining the hub virtually stationary.
2. Prior Art
It is conventional practice to locate several switches controlling motor vehicle accessories, such as cruise control and/or audio systems in the pad or hub of the steering wheel of the vehicle. By locating switches which control the cruise control and/or audio system and/or the horn, for example, in the pad or hub of the steering wheel the switches, and therefore the control of such accessories are made convenient to the driver of the vehicle. In order to reduce any confusion that may be caused by moving these switches arcuately, as the steering wheel is rotated during the steering operation of the vehicle, the pad or hub carrying these switches was arrested so that the pad or hub would remain stationary, relation to the driver, when the steering wheel of the vehicle was rotated for the purpose of steering the vehicle.
The problem of arresting the steering wheel pad is addressed in U.S. Pat. #4,808,146. This prior art patent teaches the use of a pair of external gears connected to upper and lower floating members with the steering wheel interposed between the members. A timing belt carried on the rotatable steering wheel is driven by the lower member. The timing belt drives the gear of the upper member so that the upper member and/or steering wheel hub or pad remains stationary, relative to the driver, when the wheel is rotated.
In order to maintain the timing belt at proper tension, one of the rollers supporting the timing belt is made a tension roller by connecting a biasing coil spring to the roller and to a spoke on the steering wheel. The coil spring, which is connected to a timing belt roller and the steering wheel spoke need be rather strong for the size of coil spring used due to the lack of space available. A small, strong coil spring is often too stiff to provide the resilience in the spring that is required. The compromise coil spring usually used often breaks and or fails to perform disassembly of the steering wheel is needed in order to retrieve the broken parts of the spring and/or replace the spring.